In copending application Ser. No. 484,141, filed June 28, 1974, there is disclosed an improved envelope container and the like (hereinafter simply referred to as an envelope).
Expansion envelopes are extensively used in many fields. One of many common applications of such envelopes is as a prepaid mailer for film processing or the like. The envelope can be stored and sent flat prior to use and then expanded during use sufficiently to receive and securely contain the contents therein.
Heretofore, several forms of expansible envelopes have been proposed as exemplified by U.S. Pat. Nos. 67,111; 442,842; 681,472; 2,188,730; 2,281,452; 2,460,909; 3,414,185; and 3,552,640. In the main, in each case, the prior art envelope had a single glued seam extending down the middle of the front or rear panel.
The present invention provides apparatus with improved elements and steps for scoring, applying adhesive and folding a precut one-piece unitary blank into the expansible envelope described and claimed in the aforesaid pending application.